//Given an integer array nums where the elements are sorted in ascending order, 
//convert it to a height-balanced binary search tree. 
//
// A height-balanced binary tree is a binary tree in which the depth of the two 
//subtrees of every node never differs by more than one. 
//
// 
// Example 1: 
//
// 
//Input: nums = [-10,-3,0,5,9]
//Output: [0,-3,9,-10,null,5]
//Explanation: [0,-10,5,null,-3,null,9] is also accepted:
//
// 
//
// Example 2: 
//
// 
//Input: nums = [1,3]
//Output: [3,1]
//Explanation: [1,3] and [3,1] are both a height-balanced BSTs.
// 
//
// 
// Constraints: 
//
// 
// 1 <= nums.length <= 104 
// -104 <= nums[i] <= 104 
// nums is sorted in a strictly increasing order. 
// 
// Related Topics 树 深度优先搜索 
// 👍 761 👎 0


package leetcode.editor.cn;

//Java：Convert Sorted Array to Binary Search Tree
class P108ConvertSortedArrayToBinarySearchTree {
    public static void main(String[] args) {
        Solution solution = new P108ConvertSortedArrayToBinarySearchTree().new Solution();
        // TO TEST
        solution.sortedArrayToBST(new int[]{-10, -3, 0, 5, 9});
    }
    //leetcode submit region begin(Prohibit modification and deletion)

    /**
     * Definition for a binary tree node.
     * public class TreeNode {
     * int val;
     * TreeNode left;
     * TreeNode right;
     * TreeNode() {}
     * TreeNode(int val) { this.val = val; }
     * TreeNode(int val, TreeNode left, TreeNode right) {
     * this.val = val;
     * this.left = left;
     * this.right = right;
     * }
     * }
     */


    class Solution {
        public TreeNode sortedArrayToBST(int[] nums) {
            TreeNode treeNode = toBst(nums, 0, nums.length - 1);

            return treeNode;
        }

        private TreeNode toBst(int[] nums, int start, int end) {
            if (start <= end) {
                int mid = (start + end) / 2;
                TreeNode treeNode = new TreeNode(nums[mid]);
                treeNode.left = toBst(nums, start, mid - 1);
                treeNode.right = toBst(nums, mid + 1, end);
                return treeNode;
            }
            return null;
        }
    }
//leetcode submit region end(Prohibit modification and deletion)

}